1. Field of the Invention
The present invention relates to an image search technique.
2. Description of the Related Art
Conventionally, there has been known a technique of converting the character information contained in documents printed by a printer and document images obtained by document copying into character codes using a combination of a segmentation technique and an OCR and registering them in a full-text search apparatus (e.g., Japanese Patent Laid-Open No. 9-186856). In addition, there has also been known a technique of searching document image data and a PC which has printed it and finding a cause of information leakage (e.g., Japanese Patent Laid-Open No. 2006-81119).
In an environment in which a network is used and many users use PCs, e.g., in a company, however, many printing operations are performed. Consequently, many document images are hit by search processing. This makes it difficult to find a document image that has been leaked out from the found document images and specify the PC which has printed it or the user of the PC.